The invention relates to an electroslag remelting plant comrising at least one electrode arranged in a pivotable electrode car, the electrode car being connectable to a source of electric current by means of an electrically conducting connection.
In recent years the requirement for an increase in the magnitude of the ingots produced in electroslag remelting plants (ESR-plants) has come up, thus resulting in an enlargement of the electrodes used in such plants. The increase in the diameter and the weight of the ingots and electrodes necessitates a considerable excessive proportional increase in the current required for the remelting process. In particular an ingot with a diameter of, for instance, 1000 mm requires a current of 20 kA, while a current of 30 kA will be necessary for an ingot having a diameter of 1200mm. Since the current increases to a larger extent than the diameter of the ingot, the inductive losses in the secondary circuit and the induction losses in the carrying construction of the ESR-plant also increases to a larger extent than its useful output, i.e. the efficiency of the output into the slag is reduced.
In order to remelt several elctrodes into a single block, it is necessary to effect an exchange of electrodes, for instance by means of a pivotable electrode car. With known ESR-plants, taking into consideration this requirement, there results an increase in the length and the area of the secondary electric circuit and thus an increase in its impedance.
The production of large ingots therefore necessitates first an increase of the specific energy consumption (kWh/t), and second a reduction of the efficiency factor of the secondary electric circuit, whereby a retroactive an overload of the electric network and an instability of the efficiency control is caused. Pivotable electrode cars furthermore cause a distortion of the current supply cable during the electrode exchanging processes, an additional mechanical strain on the current supply cables thus being caused.
The invention aims at avoiding these disadvantages and difficulties and has as its object to provide an electroslag remelting plant of the intitially-described kind in which the impedance of the secondary electric circuit and its magnetic effect will be reduced, and in which no distortion of the current supply cables during the exchange of electrodes will occur. The length of the current supply cable as far as to the elelctrode is also to be reduced.
These objects are achieved according to the invention in that the electrically conducting connection comprises two parts that are separable and connectable at the height of the electrode car by a pivotal movement of the same.
According to a preferred embodiment, the two parts are connectable by means of a clamping device, wherein the clamping device advantageously is designed as a tong whose cheeks are actuable by means of hydraulic or compressed-air cylinders.
According to another embodiment, the clamping device suitably is designed as a coupling.
A preferred embodiment of the electroslag remelting plant has two electrode cars, each being movable by means of a slide piece along a guide and pivotable about the guide. On each of the cars there is fastened an electrode carrier comprising an electrode gripping tong. This embodiment is improved in that for each electrode car, one part of the connection is designed as a flexible current supply cable secured by a console that is carried by the slide piece of the electrode car. A clamping device is fastened at the end of the current cable. The other part of the connection is rigidly fastened to the pivotable electrode car and is pivotable with the same. One end of this part of the connection is connected to the electrode gripping tong, and the other end is free and is designed so as to be insertable into the clamping device.
According to the invention, the distortion of the electrically conducting connection is avoided during the exchange of electrodes. The flexible connection only has to compensate for the path of the car. The connections of the secondary electric circuit for supplying and conducting away the current, are arranged closer to one another and can possibly be arranged one above the other.